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DHW Average Daily UsageRed Calc Tool User Guide

What this tool can do for you

This tool calculates average daily hot water use based on the amount of
hot water used by various appliances and use incidents. Default usage values
are included.

This tool is helpful in determining the value for the "Daily hot water usage"
input in the
DHW Systems Comparison tool.

Source: US Department of Energy

Calculated values

Average daily hot water usage

Tips

Clicking the label for any input or result will cause a
popup help box to appear. This help box includes the
allowed and normal values (for inputs).
Read more.

This tool uses number of times per week a hot water appliance is used.
The weekly value is divided by seven to determine the average daily hot
water use.

Inputs and field measurements

Hot water use for each appliance each time it is used.

Times per week each appliance is used.

Related tools

DHW Systems Comparison:
This tool allows you to calculate the annual cost of heating domestic
hot water. In addition, you may compare the annual costs of up to
three systems to a base system. Four water heating fuel types are
available; electricity, natural gas, LPG, and #2 oil. You can use this
tool for any system for which you have an energy factor (EF), including
electric resistance and heat pump systems, and various types of
oil- and gas-fired systems.

DHW First Hour Rating:
This tool helps you determine the First Hour Rating for the purpose of
sizing a storage water heater. This method is based on guidance from the
Air-Conditioning, Heating and Refrigeration Institute (AHRI), the
industry standard for sizing storage water heaters.

DHW Instantaneous Sizing:
This "solve-all" tool is used for sizing an instantaneous (tankless) hot water heater.
It can also be used to determine the maximum hot water
flow rate for a given system and temperature rise.

DHW Volume per Use:
This tool determines the volume of hot water used given an amount of mixed
(hot + cold) water used and the temperatures of the hot, cold, and mixed water.
The amount of mixed water can be specified by volume directly, or from a flow
rate and duration.

Water Flow Rate:
This is a "solve-all" tool that relates the volume of water drawn, the
duration of the water draw, and the flow rate. The primary expected use
case is determining flow rate using a test container with known volume
and a stop watch.

Related external resources

American Council for an Energy-Efficient Economy (ACEEE).
Water Heating:
http://aceee.org/consumer/water-heating#storage
Comment: This web page includes updated information
about water heater types and sizing, life-cycle cost comparisons, sizing a new
system, and efficiency standards.

California Energy Commission, Consumer Energy Center. Water Heaters:
www.consumerenergycenter.org/home/appliances/waterheaters.html
Comment: This web page includes a very good overview
of water heater issues, including pros and cons of the different types,
purchasing the right water heater, understanding energy factor, and
saving water heater energy.